1. Field of the Invention
The present invention is directed to a system and method for evaluating orthodontic treatment in an objective manner by comparing virtual models of teeth following orthodontic treatment to a targeted alignment.
2. Description of the Prior Art
Evaluation of patient's needs and treatment is invaluable for determining a prognosis and diagnosis for the patient. Precise and accurate measurement of a patient's teeth is needed for diagnosis and for evaluation. Traditional methods require locating selected patient structures and using the structures as landmarks. The use of landmarks has built in imprecision as there is some imprecision in locating the landmark twice. The problem is compounded when the landmark must be located after growth and/or treatment. Therefore, it has been difficult for practitioners to quantify and rate severity or to quantify treatment success.
Evaluation and grading also is important for ensuring that orthodontic practitioners are performing satisfactorily. In order to ensure quality standards are maintained, the American Board of Orthodontics (ABO) certifies members who pass a stringent examination including a clinical examination. The clinical examination currently involves reviewing casts from patients to assess the success and quality of the treatment provided. An objective grading system has been developed to evaluate final dental casts and radiographs. Criteria and areas evaluated include alignment, marginal ridges, buccolingual inclination, occlusal relationships, occlusal contacts, overjet, interproximal contacts and root angulation.
The evaluation is conducted by a group of members of the American Board of Orthodontics utilizing a specially developed measuring gauge. Members of the ABO involved in grading the clinical examination take measurements on various locations on several sets of plaster casts presented by candidates seeking certification. Graders make determinations regarding deviation from a desired result and points are awarded according to the success of the treatment. A score is then assigned for the clinical examination.
For each candidate, ten or more cases may be evaluated. For each case, the upper arch and lower arch are measured, meaning that more than twenty sets of measurements are made and compared for each candidate. It can be appreciated that with many candidates seeking certification and a number of graders involved in the certification, the clinical examination grading process is a time consuming endeavor than can take hundreds of man hours for each examination.
In addition to being time consuming, the examination process has several flaws. The manual measurements that are made may not be consistent from grader to grader. Precisely locating landmarks for reference points used in comparison is challenging. In addition, there is subjectivity with regard to the results and further inaccuracies that may be incorporated from the measurement process. Due to these drawbacks, it is possible for some candidates who should pass the certification process to be failed while others may pass that should not.
It can be seen that a new and improved system and method for quantifying the severity of a patient's condition and for grading orthodontic treatment is required. In addition, a method and system is needed that provides a precise and objective evaluation with a numerical rating comparing the position of the teeth to an ideal position. Such a system should eliminate the need to use traditional landmarks to make measurements while increasing accuracy and consistency over prior art manual measuring systems. Moreover, such a system should provide for greater precision than is possible with the current systems. Such a system should eliminate the need for each grader to manually measure and evaluate the final occlusion and allow all graders to utilize an accurate virtual model. Such a system should save time and effort over current systems. In addition, such an evaluation system and method should provide an electronic model suitable for use beyond grading for examination purposes. The present invention addresses these problems, as well as others associated with evaluation of orthodontic treatment.